Determination of consumption/secretion rates with single cell resolution in vivo bears a great potential for delivering detailed insights into early onset and development of various disease states in highly heterogeneous tissues and are of great importance for drug and stimulus response analysis. This information, however, is currently unavailable due to the lack of sensitivity of current technologies. On the one hand, single-cell measurements in vivo are especially challenging due to the close packaging of cells in tissues while on the other hand, analyte concentration changes induced by individual cells are extremely low. It therefore would be advantageous to have methods and devices that would overcome these challenges.